A gas turbine is configured from a compressor, a combustor, and a turbine. Air taken in through an air inlet is compressed by the compressor to become high-temperature and high-pressure compressed air. The combustor supplies a fuel to the compressed air and burns the fuel. The high-temperature and high-pressure combustion gas drives the turbine to drive a generator coupled to the turbine. In this case, the turbine is configured such that a plurality of turbine vanes and turbine blades are alternately arranged in a casing, and the turbine blades are driven by the combustion gas, so that an output shaft coupled to the generator is driven and rotated. Then, the combustion gas that has driven the turbine is discharged into the atmosphere as a fuel gas.
The combustor is provided with a plurality of main burners that performs premix combustion, and a pilot burner that performs diffusion combustion. Therefore, a diffusion flame generated by the pilot burner is used as pilot light for generating a premixed flame by the main burners. Accordingly, the premix combustion is maintained. In a typical combustor, the main burners are arranged in a circumferential direction at equal intervals outside in a radial direction around the pilot burner.
As such a gas turbine combustor, for example, there is one described in Japanese Patent Publication No. 2005-114193. The gas turbine combustor described in Japanese Patent Publication No. 2005-114193 includes a pilot nozzle provided in a central portion of a body inner cylinder, a plurality of main nozzles provided outside the pilot nozzle along the circumferential direction, and a pilot cone provided at a downstream side of the main nozzles, and an air passage that ejects the air toward a downstream side of a tip end portion of the pilot cone is provided.